As shark's sense certain irritating substances through free nerve endings (chemoreceptors) located in their mouths which are entirely distinct from their gustatory senses (ie: taste buds) the phrase Oral Repellent (in preference to the more ambiguous term “Gustatory Repellent”) is used to describe any substance that irritates either these chemoreceptors and/or the shark's taste buds upon contact with the sharks oral cavity.
Surfers apply Surfboard Wax to the top of their boards to enhance grip between their feet and the board. Different types of surfboard waxes are used for different conditions and water temperatures. Soft, tackier wax is used for cold water and harder base paraffin wax (which melts at a higher temperature) is used for warmer waters. Wax is also applied to body boards and wakeboards for the same reason. Early surfers used candle wax. Then in the 1930s they started using paraffin canning wax. This had to be melted onto the board and created a very hard surface. Sometimes sand would be added into the wax to improve grip. Then, in the 1960s waxes began to be made using oil and soft waxes like beeswax. Later, colors and fragrances were added. Today many of the waxes are synthetic blends of petroleum-based polymers. Some surfers wax the bottom of their boards with wax or fluoropolymer surface coatings to decrease resistance with the water and to protect their board.
In short, surfers have to acquire and replenish a regular supply of one or another embodiment of Surfboard Wax in order to continually coat and re-coat their surfboards and facilitate their sport. It is a cheap, repeat purchase consumable, as essential to the act of surfing as matches/lighters are to the act of smoking.
To this singular end hundreds of brands of Conventional Surfboard Wax are now commercially available, all contriving a distinct profile, but ultimately constituting little more than minor variations on the same industry standard recipe.
Thus the composition of a typical block of Conventional Surfboard Wax defaults to a uniform mixture of circa 60-75% Paraffin Wax, 15-25% Microcrystalline Wax, 5-15% Petroleum Jelly, and 0-10% of a conducive Adhesive plus optional dyes and scents for cosmetic effect.
Note that the above range of percentages enables the manufacturer to tailor the mixture to an optimum consistency and stickiness in a variety of water temperatures. Therefore for warmer water temperatures the amount of microcrystalline wax and adhesive might be increased and the amount of petroleum jelly decreased whereas for colder water temperatures the opposite would hold true.
Note also that different brands substitute different core ingredients to achieve the same objective to a largely identical effect. For example some brands substitute white oil and/or Ceresin Wax for Petroleum Jelly. Others default to an organic recipe of circa 70-80% Beeswax, 20-30% Coconut Oil, and 0-10% Tree Resin. Nevertheless in terms of function and methodology all are effectively indistinguishable.
Meanwhile, shark attack is a long recognized danger faced by ocean going humans and in particular surfers. In fact the definitive statistics collated in tandem by the Florida Museum of Natural History's “International Shark Attack Files” (ISAF) and the Shark Research Committee's “Global Shark Attack Files” (GSAF) both confirm that surfers are now shark's primary targets and are demographically at least 30 times more likely to be attacked than swimmers, divers, fishermen, etc. . . . .
Historical Development
Of the 300 plus known species of shark (elasmobranches), it is believed that only 35 species have ever attacked humans, and of these barely 15 species are recorded as inflicting repeated attacks. In fact the frequency of worldwide shark attacks on humans is minimal, averaging under 100 unprovoked incidents per year with less than 30% proving fatal.
But despite these statistics, the primordial fear of shark attack has always pre-occupied man and came starkly to the fore during the Second World War when U.S. service personnel were deployed in the shark infested waters of the South Pacific. Thereafter the private and public sector have labored to develop chemical shark repellents potent enough to deter the most aggressive orders of elasmobranches such as carcharhinoformes and lamniformes and afford daily protection and above all peace of mind to the millions of ocean going humans worldwide.
Since then researchers have formulated numerous experiments (bio-assays) to test whether prospective repellents evoke a flight response in sharks. For example, in one such bio-assay a potential repellent of set volume and concentration is introduced into a fixed position in a shark tank and the degree of aversive shark response to that portion of the tank is then recorded.
Another comparable bio-assay introduces a potential repellent of set concentration and volume into the feeding zone of sharks and monitors whether the sharks then flee the vicinity and/or cease feeding activity.
An alternate bio-assay measures the effect of potential repellents on a shark that is trapped in a state of paralysis known as “tonic immobility.” Tonic immobility is typically induced when a shark's body is inverted along its longitudinal axis and can persist for up to a quarter of an hour. Researchers then use this 15 minute window to establish behavioral controls and to study the effects of precise concentrations of prospective repellents on the shark. According to this bio-essay a successful repellent should waken the shark from its tonic state.
But of all these bio-assays the benchmark was set in 1985 when Johnson & Baldridge and the U.S. Navy established the definitive government target of finding a chemical that would repel sharks when dispersed in a cloud formation in open water at a concentration of 0.1 parts per million (i.e.: 0.1 ug ml-1).
The experiment (“The Johnson & Baldridge Test”) stipulated the steady state dispersal of 100 mg of a prospective repellent from a point source into a 6 cubic meter boundary of water over a 3.5 hour period to achieve the proposed 0.1 ppm concentration target in a cloud formation around a potential prey. If sharks then demonstrated strong aversive behavior under these conditions, the criteria was considered satisfied and the repellent was deemed to be “effective”.
That goal has yet to be officially achieved. But elasmobranch research history is littered with many near misses and failures.
One of the most notable and earliest of these failures occurred in 1944 with the development of the U.S. Navy's “Shark Chaser” chemical repellent, a mixture of 20% copper acetate and 80% nigrosine dye which was issued to high risk combatants in the Pacific despite being entirely ineffective.
Since then numerous alternative shark repellents methods have been explored with varying degrees of success and practicality including electrical devices (Gilbert & Springer 1963, Gilbert & Gilbert 1973), acoustic devices (Myrberg et al. 1978, Klimley & Myrberg 1979), and visual devices (Doak 1974).
But of the purely chemical methodologies investigated such as toxins and saponins, etc. . . . (Tuve 1963, Clark 1974, Gruber & Zlotkin 1982, Zahuranec & Baldridge 1983) none were considered sufficiently effective (Sisneros (2001)).
A marked advance did occur in 1974 with Eugenie Clark's discovery of the toxin “pardaxin”, an amino acid polypeptide secretion of the Moses Sole Fish (Pardachirus marmoratus) which attacked shark's respiratory systems via the gill rakes with significant repellent impact.
However subsequent research revealed that pardaxin and similar natural compounds like pavonin and mosesin were expensive to produce and unstable to store at room temperature. More importantly, it transpired that they were only chemically effective as taste effective (gustatory) repellents rather than smell effective (olfactory) repellents and were thereby deemed functionally impractical to administer at the requisite concentrations as they had to be actively squirted directly into the shark's mouth at the moment of attack as opposed to being passively dispersed in the surrounding water to preemptively target the shark's chemo receptors as per the Johnson & Baldridge test.
A further potential breakthrough was curtailed on identical grounds when Zlotkin noted that pardaxin and its organic affiliates exhibited surfactant properties (i.e.: they reduced surface tension) and speculated that cheap synthetic surfactants such as alkyl sulfates (i.e.: commercial soaps) might also prove viable.
Indeed initial tests by other investigators supported his hypothesis and confirmed that a range alkyl sulfates such as sodium lauryl sulfate (SLS), lithium lauryl sulfate (LLS), sodium octadecyl sulphate (SOS), and sodium dodecyl sulphate (SDS) were all even better than pardaxin at repelling Lemon, Blue, and Great White Sharks and did so with an increasing effectiveness depending on their carbon chain lengths (see “The Behavior and Sensory Biology of Elasmobranch Fishes: An Anthology in Memory of Donald Richard Nelson” (Tricas, T. C. & S. H. Gruber (ed.) (2001)).
But again, subsequent research cited by J. A. Sisneros confounded this breakthrough when he observed that even SDS (the most potent of the alkyl sulfates) was only effective as a repellent at concentration of 43.6 ppm and thus (like pardaxin) still fell short of the Johnson & Baldridge concentration benchmark of 0.1 ppm when dispersed in the surrounding water.
Since then interest has veered back to Semiochemical and even Capsaicinoid based repellents as potential solutions to the Johnson & Baldridge litmus test.
Semiochemicals generically encompass pheromones, allomones, kairomones, attractants, repellants and substances that carry a chemical message and as early as 1978 Hodgeson & Mathewson were describing their irritant effect on lemon sharks. However even then it was recognised that the concentration levels needed to provoke a strong adverse response were pushing the functional limits of the the shark's chemoreceptors. Nevertheless one U.S. based company is currently pursuing two substantiative patents entitled “Elasmobranch-repelling compounds, methods of use (and devices)” which forward prospective solutions based on semiochemicals extracted from shark carcasses (see PCT/US2006/00503 & PCT/US2006/02291 respectively).
Capsaicinoids, meanwhile, are a naturally occurring family of highly pungent compounds responsible for the burning taste produced by all hot peppers. The most potent of these is capsaicin which has been a staple animal deterrent for decades and is the core ingredient in anti-personnel devices such as pepper spray. Capsaicinoid pungency is measured on a gustatory sliding scale of 0-16,000,000 developed by William Scoville in 1912. According to this scale a “Scoville Value” of 1 can barely be tasted, whereas a jalapeno pepper has a value of circa of 2,500-5,000, cayenne pepper has a value of 30,000-50,000 (which is is more than sufficient to taste aversive to a shark) and anything with a value of above 200,000 would cause permanent damage to skin and nerve endings.
Types of Repelling Actions
There are broadly two types of Shark Repellent Device, each with its' own shortcomings with respect to achieving an optimum balance between cost, effectiveness, and convenience:
(1) The first type falls outside the scope of this patent and include the various electrical, mechanical, and sonic repellents. Though arguably effective, these devices are often expensive and/or cumbersome, vulnerable to malfunction, and generally require waterproof electrical batteries with limited energy supplies in order to operate.(2) The second type includes the various Chemical Repellents, to which this patent pertains. Note that these devices are by nature dual faceted, a fact acknowledged in paragraph 26 of a recent capsicum related shark repellent patent (U.S. Application 179118) which freely concedes that “ . . . it is recognized in this invention that a chemical deterrent does not work alone by itself without a device constructed to repel sharks in certain and determined circumstances.”
Thus all Shark Repellent Chemical Devices combine a Chemical Agent in an embodiment that simultaneously provides a functional Method of Delivery for that Agent's deployment. In this respect there are broadly four classes of viable Shark Repellent Chemicals:                A) Organic Surfactants—such as pardaxin, pavonin, mosesin and assorted saponins (including phytolacca americana, eremocarpus setigerus, and chlorogalum pomerolk sallet based compounds), etc. . . . .        B) Synthetic Surfactants—such as the alkyl sulfates (including sodium lauryl sulfate, lithium lauryl sulfate, sodium octadecyl sulfate and sodium dodecyl sulfate based compounds), etc. . . . .        C) Capsaicinoid based compounds.        D) Semiochemical based compounds.        
Simultaneously there are broadly two established Methods of Delivery for deploying these Chemical Agents:                A) “Continual Dispersion” devices function by continually leaking an ongoing percentage of the Chemical Agent into the surrounding waters in a cloud formation of sufficient concentration to repel any shark intrusion into the immediate vicinity of its human prey. Devices of this type are therefore compromised by the untenably short term, wasteful and expensive nature of their delivery, and above all by their uniform inability to achieve and maintain the 0.1 part per million concentration benchmark dictated by Johnson & Baldridge.        B) Conversely, “One Shot” Devices require that the Chemical Agent be retained in a sealed configuration which is then manually breached by the human target and targeted directly at the shark in response to an imminent attack. While negating the shortcomings of the “Continual Dispersion” method and potentially satisfying the dictates of the Johnson & Baldridge concentration target, this ad hoc approach is itself compromised by its' short term effectiveness and unrealistic reliance on the human target's continual vigilance in the face of a stealthy physically superior predator in an already hostile and uncertain environment.Problem Analysis        
It can therefore be seen that the historic inability of prospective Shark Repelling Devices to achieve their objective by chemical means and in accordance with the Johnson & Baldridge concentration target is rooted in a fundamental paradox.
On the one hand, according to Eugenie Clarke's own Mote Laboratory, they have failed because their efficacy in sea situations is minimal due to the rapid dilution of chemicals in seawater.
On the other hand, all attempts to redress this failure have proved functionally counterproductive. To quote J. A. Sisneros criticism re SLS (and by implication all comparable surfactant based devices), . . . “the greatest limitation of SLS is that it is required to be squirted into the mouth of an approaching shark. It is not effective in surrounding-cloud mode dispersions. Therefore, SLS is only useful when the user can clearly see an approaching shark and orchestrate the delivery of SLS into the animal's mouth.”
In other words, thus far all combinations of Chemical Agent and Method of Delivery have proved mutually incompatible. Either a viable (0.1 ppm) concentration of the Chemical Agent has been deployed via an impractical Method of Delivery (as in the squirt approach), or a functional Method of Delivery has been utilized to deploy an insufficient/unsustainable concentration of the Chemical Agent (as in the cloud dispersal approach). But to date no single Device has viably combined both elements.
It is however interesting to note that, irrespective of their differences, all these Devices share two fundamental similarities:
(1) Firstly, they all share a common Design Objective, namely to decrease a potential victim's risk of injury from shark attack in a relatively cost efficient, effective, and convenient manner.
(2) Secondly, they all share a common Design Dynamic, namely the pre-emptive deployment of a shark repelling agent via one of the two aforementioned Methods of Delivery (i.e.: “Continual Dispersion” or “One Shot”) in order to deter an attack prior to the shark first biting it's target.
It is an objective of this invention to address the above discussed problems.